are both flights on AC and does your travel end at IAD? If so, this could a problem ticket -- cabotage
If the second flight is UA operated, it will be OK


probably a better question for a Canadian or AC forum. but in most countries, transit passengers are not subject to the local countries customs / immigration. Whether USCBP will accept bags that have pass-thru a non-USA airport, that feels unlikely but it is outside my knowledge.

Pearson has an awesome online connection guide, which says you do not have to clear immigration and customs at YYZ. Toronto Pearson - Connecting

I'm assuming you're on UA YYZ-IAD, otherwise your ticket would be illegal.

This.
There is different inventory, and therefore prices when using different country sites.
However it doesn't block you from booking from sites outside your own country, so always look around.

Thanks, the customs process turned out to be quick and smooth - to the point where I might actually consider flying through YYZ for my TPAC trips.
And yes, SFO-YYZ was in AC, and YYZ-IAD will be on UA.

Thanks again!

So if the US / UK inventories are J9 D9 Z6 / J9 D1 Z0 respectively, and you search with US location to find a Z fare but then enter a UK card (which triggers a switch to UK as POS) does it still permit you to purchase?

No. The POS change will trigger an inventory revalidation and you'll get a generic error. You can, however, pay with a UK card as a US-based OTA to ticket with US inventory.

Was CPU upgraded for my first flight of the year - cleared into PZ class as indicated on the receipt. (and as in the past)

However, the mileage plus status shows I was credited for "ZY Class". Miles earned matches the expected PQD * 11, but I got 1.5 PQS instead of 1.

I haven't had this happen before, wondering if it's been seen before.

What was the original fare basis, and did anything unusual happen to the ticket?

Original fare was in W, one way SEA - SFO. Nothing unusual happened - got upgraded about 30 minutes after check in (at T-24), no irrops or anything.

Weird. I have had unusual postings of the ilk before, but almost always with tickets that have been through a lot more than that.

Update. It turned out to be an IT an issue and neither of us got SSSS. Probably because it was partner award booked with Singapore air. At the airport they weren't able to print our boarding passes and they split the reservation to fix it.

Yes but there may or may not be space, so you may have to make a choice between waiting for a flight with space or dropping back to economy to travel sooner. If you end up in economy, you can request a refund (www.united.com/refunds) for the upgrade fee.

Some agents will be more willing to do so than others.

Missing a flight when you're booked up front often leads to a conundrum: fly in Y or wait for a seat in J/F. It's common for the premium seats to fill up, meaning your wait can be substantial.

Seat Assignment Refund